Pipe cutter



July 26, 1932 H. M. MYRACLE PIPE'CUTTER Filed Jan. 19, 1931 ATTONEY Patented July 26, 1932 UNITED STATES PATENT oI-FlcE HOBART M. MYRACLE, OF OKLAHOMlA CITY, OKLAHOMA, ASSIGNOR TO AMERICAN IRON AND MACHINE WORKS COMPANYQ/OF'OKLAHOMA CITY, OKLAHOMA, A CORPORATION or OKLAHOMA f PIPE CUTTER Application filed January' 19, 19,31. Serial No. 509,865.

My invention relates to pipe vcutters and more particularly to a device of that character .for severing a string of drill pipe or well casing topermit salvaging of a portion of the string when it is impossible to remove the entire string from the well due to caving or other causes.

'Cutters heretofore employed have been equipped with two blades and the use of this structure results in binding and chattering of the blades and uneven cutting of the pipe, due to a departureof the cutting devicefrom Vconcentric relation with the pipe.

' The principal object of my invention, therefore,is to provide a cutter that will automatically maintain a position concentric-ally within the pipe due to the particular mounting and-number of cutter blades employed, thereby insuring a rapid and uniform cutting operation. l

A further object of the invention is to provide a simple device, constructed of parts that may be easily assembled and readily replaced when worn or broken.

In accomplishing these and other object ofthe invention, Iy have. provided improved details of structure, the preferred form of which is illustrated in the accompanying drawing, wherein:

Fig. 1 is a central vertical section through a cutter in cutting relation with a drill pipe, the guide member for the cutter being shown in elevation. i

Fig 2 is a similar sectional View illustrating the drill pipe completely severed and ythe cutter blades withdrawn into their housing for withdrawal from the drill pipe.

Fig. 3 is a perspective view of the several cutter members in spaced relation.

Referring more in detail to the drawing:

1 designates a string of drill pipe consisting of tubular sections joined, together by threaded coupling members 2 and 3 having aligning reduced bores 4.

The cutter embodying my invention and generally designated 5, is preferably secured to the externally threaded lower end 6 of a string of well tubing 7 by a coupling '8 having upper and lower internally threaded -sockets 9 and 10 for respectively receiving the lower end of the tubing and the upper end of a tubular body member 11 of the pipe cutter.

The body member is preferably provided with a reduced threaded neck 12 for seatlng in the lower socket 10 of the coupling so that the outer periphery of the body member will be flush with the outer face of the coupling andwith the outer face of a pilot or guide member 13 secured to the internally threaded lower end 14 of the body member by a reduced externally threaded neck 15. The aligning outer walls of the coupling, body and guide members permit the device to pass readily through the bores 4 of the couplings, entrance into the couplings being facilitated by a rounded lower end 16 of the guide member.

A further reduced continuation of the neck 14 comprises a head 17 having a plurality of inclined notches 18 for directing cutter blades 19, presently more fully described,

through aligning lateral slots 2O formed inl the wall of thebody member.

Provided in the coupling 8 is a constricted p boreor guide opening 21 for slidably re-` ceiving an actuating stem 22 having a plurality of fiat faces 23 on its lowerend, each provided with a laterally extending bearing pin 24 for pivotally mounting one of the cutter blades 19.

The cutter blades are preferably of arcuate form, tapering to a cutting edge 25, so that their curved faces 26 will slidingly engage th'e inclined faces of the notches 18 to direct the cutting ends of the blades at substantially right angles into engagement with the casing wall.

In order to normally retract the cutter blades into the body member, a spring 2.7 is mounted over the actuating stem and 1s seated in the upper socket 9 of the coupling 8, being retained therein by a piston 28 se-l 'cured to areduced threaded end 29 of the stern by a washer 30 and nut 31.

Various means may be employed for limiting retractive movement of the stem, but I have provided for this purpose an enlarged portion 32 adjacent the lower end of the stem to form astop shoulder 33 for engaging the coupling 8.

Assuming a device to befconstrueted and assembled as described, the operation for cutting a pipe in a well would beV as follows: i

The cutter, after being assembled, is at` tached tomthe lower end ofthe tubing and ber and have their cutting edges brought blades have` severed the drill pipe. rUpon releasefof pressure from the tubing the spring elevates the pistonwithin the tubing, thereby retract'ingthe blades within the body member, asdisclosed in Fig. 2, and permit-` ting vice from the pipe.

I prefer to employ three blades, as shown` in the drawing, the principal purpose of i lingnotches respectively aligning with said slots, a stem reciprocably `mounted in the` i body member, threercutters'pivotally mounted at one end and provided with cuttingij l edges on their opposite endson the lower end of said stem, said cutters adapt-ed for engaging said notches andto` `be directed through the slots upony downward movement i y of the stem in the body member, thereby bringing said cutting edges into-.i engagement with said well casing tor cutting the ."same, said cutters also preventing lateral movement of said tubular member, `means for normally retracting said cutters `into the body` i member, and stop means onthe body mem-` ber and stem for limiting rctraetivc movement of the stem.;

In testimony whereofl atiiximy signature.

HOBART LL MYRACLE. A

removal ot the tubing and cutting dei i which, being that the equal spacing of three i i i blades will tend to produce a uniform radial pressure on the body member, thus maintain-I ing concentric relation ot the lower endet u i the bodymember with the pipe. y

Vhat Iclaim and desire to secure ters Patentis: i

1. An internal cutter for a cylindrical member, a tubular bodymember having three by Letlateral slots, an extended guide member .i threaded into the lower end of vsaid body member, a head on the guide member eX- "tending upwardly into the body member,

said head having notches in its end respectively aligningwith said slots, a stem reciprocably mounted in the body member,

three lcutterspivotally mounted at one end..`

on the end of said stem, the opposite ends of said cutters being provided with cutting edges.. and adapted to engage said notches to be directed through the slots upon `downward movement of the stem in the bodymeminto cutting Vengagement with the interior of the cylindrical member and also maintaining said body member in concentric relation to said cylindrical member, and means for normally retracting said cutters into the body member. i y

2. An `internal cutter for a well easing joined by couplings having constricted bores, a tubular body member having three lateral slots, "aiguide member associated with the y body member and adapted torengagea boreof a coupling, said body Vmember and guide member having equal Voutside diameters, a head on the guide member extending up-w wardly into the body member, said head hav- 

